The Collaborative International Dictionary of English v.0.48:

Piffle \Pif"fle\, v. i. [imp. & p. p. Piffled; p. pr. & vb. n.
   Piffling.]
   To be sequeamish or delicate; hence, to act or talk
   triflingly or ineffectively; to talk nonsense or about
   trivial matters; to twaddle; piddle. [Dial. or Slang]

   Syn: chatter, palaver, prate, tittle-tattle, twaddle, clack,
        maunder, prattle, gibber, tattle, blabber, gabble.
        [Webster 1913 Suppl. + WordNet 1.5]

   2. To act in a trivial or ineffective way.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

piffling
    adj 1: (informal) small and of little importance; "a fiddling
           sum of money"; "a footling gesture"; "our worries are
           lilliputian compared with those of countries that are at
           war"; "a little (or small) matter"; "a dispute over
           niggling details"; "limited to petty enterprises";
           "piffling efforts"; "giving a police officer a free meal
           may be against the law, but it seems to be a picayune
           infraction" [syn: fiddling, footling, lilliputian,
           little, niggling, piddling, piffling, petty,
           picayune, trivial]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "piffling":
   Mickey Mouse, jerkwater, measly, niggling, one-horse, peddling,
   pettifogging, petty, picayune, picayunish, piddling, pimping, poky,
   punk, puny, small-beer, small-time, tinhorn, trifling, trivial,
   two-bit, two-by-four